This invention relates in general to new and useful improvements in a rack aligning fixture. More particularly, this invention relates to a fixture for aligning the racks of a rack and pinion mechanism of the type used in driving straight line shears for cutting glass runners into individual gobs.
U.S. Pat. No. 4,215,611 to Francis A. Dahms, granted Aug. 5, 1980, assigned to the assignee of the present invention, discloses a straight line shear wherein there are two slides mounted for guided movement towards and away from one another, and arranged in opposed relation. The slides carry cooperating blades. The slides are driven by racks which are interconnected by a pinion gear. The drive unit is in the form of a double-acting air cylinder or linear air motor which is coupled to one of the racks between that rack and an associated one of the slides.
In assembling a rack and pinion mechanism, particularly the rack and pinion mechanisms of the type used in a straight line shear mechanism, it is essential prior to placing the pinion gear in position that the face of the teeth of the racks be parallel with each other for proper mating of the teeth with the pinion gear teeth. In the past this parallelism has been established by incorporating additional features into the assembly such as keys and keyways properly oriented to position the rack teeth in the desired position. The inclusion of keys and keyways understandably is expensive from the standpoint of machining of the keys and keyways, in addition to the cost of the component parts.
Accordingly, there is a need for an alignment fixture and method of alignment which is inexpensive and which is simple in operation.
A primary object of the present invention, therefore, is to provide a means of aligning the rack teeth faces of a rack and pinion mechanism at the time of assembly without need to provide additional machining of the individual parts.